The present invention relates to a shift lock device and, more specifically, to a shift lock device of a shift-by-wire type shift apparatus.
Conventionally, a driver of a vehicle designates a shift position in an automatic transmission by operating a shift lever of a shift apparatus. A shift lock device locks the shift lever in a park position (parking) so as to restrict movement to another position. The lock is released by, for example, operating a brake pedal. For example, Japanese Laid-Open Patent Publication No. 10-59132 discloses a shift lever apparatus that moves back and forth in a linear shift gate. The park position is located on one end of the shift gate. When the shift lever moves to the park position, a lock pin of an actuator (solenoid) engages a projection formed on the shift lever to lock the shift lever.
For example, if an ignition switch ON output signal and a brake pedal operation output signal are sent to an electronic control unit (ECU) and a lock release button is pressed, the actuator is driven to disengage the lock pin from the projection. The shift lever may then be moved from the park position P to a reverse position R, a neutral position N, or a drive position D.
Japanese Laid-Open Utility Model Publication No. 7-20460 discloses a shift lever apparatus provided with a restriction mechanism that restricts movement of a shift lever from the neutral position N to the reverse position R to prevent the shift lever from being moved from the drive position D to the reverse position R.
A shift lever apparatus is provided with a switch that detects movement of the shift lever and a solenoid that operates in response to a detection signal from the switch. When the vehicle velocity is less than a predetermined value, the shift lever is movable from the neutral position N to the reverse position R. When the vehicle velocity exceeds the predetermined value, the solenoid moves an engaging member to engage the anchor member and the shift lever with each other and restrict the movement of the shift lever from the neutral position N to the reverse position R.
In recent years, a so-called shift-by-wire automatic transmission has been proposed in which a switching operation of a shift lever is converted into an electrical switching signal to operate an actuator with the switching signal and switch a manual shift valve. In the shift-by-wire automatic transmission, the shift lever may be operated with a small amount of force, and the shift range may easily be switched by an electrical switching signal. Moreover, the shift lever and shift apparatus may be reduced in size.
In the shift-by-wire automatic transmission, as the sizes of the shift lever and shift apparatus are reduced, it becomes necessary to reduce the size of the actuator, which locks the shift lever. However, if the size of the actuator is reduced too much, it becomes difficult for the actuator to have sufficient strength for restricting the movement of the shift lever. Moreover, the mechanical structure for restricting the movement of the shift lever from the neutral position N to the reverse position R is complicated, and it is also difficult for the size of this structure to be reduced.
Furthermore, the actuator is used only to restrict movement of the shift lever from the park position P. Accordingly, a separate actuator is needed to restrict movement from the neutral position N to the reverse position R.
It is a first object of the present invention to provide a shift lock device that can be reduced in size.
It is a second object of the present invention to provide a shift lock device that locks a shift lever in a park position and restricts movement of the shift lever from the neutral position to the reverse position with a single actuator.
In a first perspective of the present invention, a shift lock device for a shift lever that selects shift positions in a shift apparatus used in an automatic transmission of a vehicle is provided. The shift lock device includes a fixed plate having a shift gate that allows movement of the shift lever to each of the shift positions and a movable plate facing the fixed plate and being movable in a direction intersecting a moving direction of shift lever. The movable plate has a corresponding gate that has an area greater than the area of the shift gate. An actuator is connected to the movable plate to move the movable plate between a first position and a second position. The corresponding gate of the movable plate allows movement of the shift lever to any shift position at the first position and restricts movement of the shift lever in cooperation with the fixed plate at the second position.
In a second perspective of the present invention, a shift lock device for a shift lever that selects shift positions including a park position, a neutral position, and a drive position in a shift apparatus used in an automatic transmission of a vehicle is provided. The shift lock device includes a fixed plate having a shift gate that allows movement of the shift lever to each of the shift positions. The shift gate has a first crank-shaped opening, which corresponds to the park position, and a linear opening, which corresponds to the neutral position and the drive position and which is formed continuously from the first crank-shaped opening. A movable plate faces the fixed plate and is movable in a direction intersecting a direction in which the shift lever moves. The movable plate includes a first crank-shaped opening and a corresponding gate, which is formed continuously from the first crank-shaped opening and is wider than the linear opening. An actuator is connected to the movable plate to move the movable plate between a first position and a second position. The corresponding gate of the movable plate allows movement of the shift lever to any shift position at the first position, At the second position, the first and second crank-shaped openings lock the shift lever in the park position, and the linear opening and part of the wide opening restrict movement of the shift lever between the drive position and the neutral position.